From: Peter F. Patel-Schneider (pfps@research.bell-labs.com)
Date: 05/16/02
From: Dan Connolly <connolly@w3.org> Subject: re: RDF Core working drafts Date: 15 May 2002 16:46:25 -0500 > > 3/ The semantic action for an empty subject on a nodeElement could be > > executed even for element nodes with an rdf:ID or rdf:about attribute. > > This is probably benign, but would cause the blank node identifier > > generator to be pointlessly run resulting in distinct (but > > model-theory-equivalent) sets of n-triples resulting from a single > > RDF/XML document. > > I don't think I understand this; maybe an example would help? Suppose you have <foo rdf:ID="bar" /> It is permitted to run the blank node identifier generator when processing this description because the semantic action for this can be performed before the semantic action that sets e.subject from rdf:ID. > > The theory of literals in the model theory is very weak. This means that > > there is no relationship whatsoever between literals the differ only on > > their language (or on the presence of a language). > > Hmm... I don't see why it would/should be otherwise. Users may have different expectations, so there should be a clear statement that this is the case. > > The abbreviation example incorrectly states that rdf:resource is (always) > > used when ``the property value is another (existing) resource''. There > > are, instead, lots of ways to do this in RDF/XML. > > > > This section retains the notion that rdf:about is used for existing > > resources and rdf:ID is used for new ones. This is no longer correct, > > How so? There is no need to use rdf:ID. It is possible to have an rdf:about for a resource before any rdf:ID for that resource. > Are you referring to this text? > > > So far, we've been describing resources that have been defined (and > given URIs) already. For instance, in our initial examples, we've been > providing descriptive information about example.org's web page, > whose URI was http://www.example.org/index.html. We referred to this > resource (defined elsewhere) using an rdf:about attribute. However, > obviously we also want to be able to define new resources. For > example, suppose a company, example.com, wanted to provide an > RDF-based catalog of its products as an RDF/XML document, > identified by http://www.example.com/2002/04/products. > Within that resource, each product might be given a separate > RDF description. An example of one of these descriptions (the > catalog entry for a tent) might be: > > 1. <?xml version="1.0"?> > 2. <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" > 3. xmlns:ex="http://www.example.com/terms/"> > [...] > > I don't see anything incorrect there. rdf:ID can still be used that > way. Yes, but the indication here is that rdf:ID is the only way to define new resources, which is certainly not the case.n > > nor > > is it the case that there must be at most one rdf:ID for a given URI in a > > document. > > Yes, it is the case. > > "Constraint: The names used as values of rdf:ID and rdf:bagID attributes > must be unique in a single RDF/XML document..." > http://www.w3.org/TR/2002/WD-rdf-syntax-grammar-20020325/#idAttr What does the statement from the chair http://lists.w3.org/Archives/Public/www-rdf-comments/2001OctDec/0385.html that states that rdf:ID="foo" is a synonym for rdf:about="#foo" mean then? I think that a reconcilliation between these two incompatible points of view is needed. The limitation to ``within a single RDF/XML document'' is rather strange. If I can have Doc 1: rdf:ID="http:x" Doc 2: rdf:ID="http:x" why can't I have Doc 1: rdf:ID="http:x" rdf:ID="http:x" > > The example for parseType="Resource" misleadingly implies that an rdf:ID > > attribute here would provide a name for the resource. Instead an rdf:ID > > here is a reification mechanism. > > Which example? I don't see the problem. Two paragraphs after Figure 8 there is a strong indication that rdf:ID with parsetype=resource will give the resource an ID. This is not the case. > > 4. Defining RDF Vocabularies: RDF Schema > > > > This section give the impression that RDF Schema is nothing more than a > > well-known set of names, to be used in RDF. Instead RDF Schema is a > > semantic extension to RDF. > > It says that the well-knonwn names don't have > related well-known meaning/semantics/axioms? > Where? There is no indication that such is needed in RDF Schema. Readers may get the impression that RDF Schema is given meaning by an RDF document, nothing more. > > This section blurs the distinction between RDF > > and RDF Schema, particularly in its treatment of rdf:type. > > Hmm... I haven't read it closely enough to know what you mean by that, > I guess. The impression there is that rdf:type is given a meaning by RDF Schema. However, all that RDF Schema does is gather resources that are RDF types into a grouping called rdfs:Class. > > Overall comments: > > > > The lack of any treatment of datatyping in RDF (except for a few mentions > > that state that datatyping is deferred to the future) is surprising, and > > disappointing, particularly in light of the mention of XML Schema datatypes > > in the RDF Core WG charter. > > Yes, it's frustrating that we didn't get a datatyping WD out. > > -- > Dan Connolly, W3C http://www.w3.org/People/Connolly/ > peter
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